1. Technical Field of the Invention
This invention relates to substrate processing apparatus for processing substrates, for example, semiconductor wafers, glass substrates for LCD, etc.
2. Description of the Related Art
In the manufacturing process for semiconductor devices, there exists a problem that when a semiconductor wafer (referred as “wafer”, hereinafter) has a metallic film laminated thereon, the metallic film is easy to separate from the peripheral part of the wafer. If such a separation originates in the peripheral part of the wafer, the separation may spread gradually to extend over an area where a semiconductor device is to be built. In order to prevent the occurrence of the above phenomenon, there has been attempted a step of removing a metallic film (part) formed on the peripheral part of the wafer in advance. Note, this removal step will be referred “peripheral-part removing process”, hereinafter. FIG. 21 is an explanatory view of a method of carrying out the peripheral-part removing process by using the conventional substrate processing apparatus. According to the method, a wafer W is rotated by a holder. While rotating the wafer W, a processing liquid is supplied to the peripheral part of the wafer W through a liquid supplier 140, such as nozzle, thereby to eliminate the circumferential corner of a metallic film 141 obliquely. On the other hand, through a supply unit 142 arranged above the center of the wafer W, pure water is supplied to the wafer W in order to prevent the processing liquid from adhering to the other wafer portion except an objective area to be supplied with the processing liquid and also order to sweep away the processing liquid toward the circumference of the wafer.
In order to produce enough centrifugal force to sweep away the processing liquid toward the circumference of the wafer, however, it has been required that the substrate processing apparatus can rotate the wafer at considerable high-speed revolutions. Additionally, as the pure water is supplied to the whole wafer in spite of processing the peripheral part of the wafer only, the whole wafer has to be dried throughout. Therefore, these requirements incur a deterioration in the throughput of the substrate processing apparatus in processing the wafers.